Influence of Salivary Macromolecules and Fluoride on Enamel Lesion Remineralization in vitro

Abstract

The aim of this study was to investigate the influence of salivary macromolecules on enamel lesion remineralization in the presence or absence of fluoride. Paraffin-stimulated whole saliva was centrifuged, and the supernatant was dialyzed in 1,000 molecular-weight cutoff dialysis tubes, first against a phosphate buffer and then against a mineral solution containing Ca and phosphate. Artificial subsurface lesions of human enamel, created in pH 4.5 acetate buffer, were remineralized for 28 days in 4 remineralizing solutions: group C – mineral solution as a control; group S – mineral solution + dialyzed saliva; group F – mineral solution + 1 ppm F; group SF – mineral solution + dialyzed saliva + 1 ppm F. Changes in relative mineral concentration in the lesions were assessed by transverse microradiography. The results showed statistically significant mineral gains in the lesion body in groups C (ΔZ = 3,254 ± 1,562% ×µm) and SF (ΔZ = 2,973 ± 1,349% ×µm), but not in groups S (ΔZ = 5,192 ± 1,863% ×µm) and F (ΔZ = 4,310 ± 1,138% ×µm) compared with the baseline group (ΔZ = 5,414 ± 461% ×µm). It was also found that the mineral density at the surface layer in group F (75.0 ± 15.7%) was greater than that in the baseline group (30.1 ± 12.3%) with statistical significance, but not in group SF (39.9 ± 16.5%). It was concluded that the macromolecules inhibited lesion remineralization fundamentally but that these molecules, in the presence of fluoride, seemed to play an important role in the continuation of remineralization by reducing mineral gains at the surface layer.

Comparison of resin-based and glass ionomer sealants with regard to fluoride-release and anti-demineralization efficacy on adjacent unsealed enamel

“…The specimens were incubated in a newly developed AS that contained casein to better simulate the human salivary composition. The role of salivary proteins in controlling fluoride availability has been investigated in vivo 28,29) and overlooking the effects of these proteins may yield results that are not congruent with the remineralization phenomenon observed in subsurface enamel lesions in vivo 30) . It was also recently reported that casein can mimic the mineral regulatory functions of salivary phosphoproteins, such as stabilization of supersaturation of AS regardless of presence and absence of F − in AS, and inhibition of unwanted apatite crystals growth as well as superficial fluoridated apatite precipitation on sound enamel; which will never happen in vivo situation 24) .…”

Chemical alteration by tooth bleaching of human salivary proteins that infiltrated subsurface enamel lesions —Experimental study with bovine lesion model systems—

“…by protecting against tooth wear, inhibiting spontaneous calcium phosphate crystallization in the formation of calculi, controlling microbial adherence, and inducing permselective ion transport. Salivary proteins have also been implicated in the continuation of remineralization by reducing excess mineral gains at the surface layer in the presence of fluoride 11) . In addition to preventing undesirable precipitation of calcium phosphate, we speculated that these proteins can inhibit desired remineralization of subsurface lesions.…”

An approach to normalizing micro-CT depth profiles of mineral density for monitoring enamel remineralization progress

“…Most of these studies were carried out using traditional Transversal Micro Radiography (TMR) method 4,5) . Although TMR has been used as a gold standard for quantifying mineral gain and loss, the method is usually destructive to enamel and dentin tissues, and they did not show any longitudinal mineral changes in exactly the same lesions.…”

“…So, it would be quite diffi cult to perform a long term period of de-and remineralization experiments 4) . Dowker et al reported the development of subsurface enamel lesions using micro-CT 5) . Huang et al showed mineral density profi le of enamel white spot lesions using micro-CT 6) .…”